WHEN is a change of heart not a change of heart? When it’s Rudy Giuliani‘s change of heart.

Rudy did something peculiar last week. His campaign used the front page of The New York Times to announce that he’d be changing his approach on the subject of hot-button social issues.

Rudy would, we were told, stop trying to straddle. He would speak forthrightly about his support for abortion and gay rights and speak on behalf of tolerance.

Then he went out over the weekend and . . . said exactly the same things he’d been saying.

He said he opposes abortion – stands in moral opposition to it, in fact – but believes a woman has a right to choose it. He said he will appoint “strict constructionist” judges but will not ask them their views of abortion or even, it appears, their view of the highly controversial Roe v. Wade decision.

He said we need to respect opposing views and not think that people who hold them are immoral. He said he supports gay rights but opposes gay marriage.

And presumably, in tonight’s second GOP presidential debate, he’ll try to say all this again – though perhaps in a more coherent way than he did last week.

Memo to The New York Times: The Rudy Giuliani campaign just de-pantsed you. You got sold a bill of goods. Meet the new boss – same as the old boss.

Maybe the packaging will be slightly different, but there’s not a millimeter’s difference between Rudy 1.0 and Rudy 2.0.

And that’s interesting, and not just because it’s embarrassing for The New York Times.

Rudy has decided to take the most unconventional approach possible on these matters: He’s embracing the mantle of choice and calling himself a supporter of gay rights – while holding policy positions on these matters that don’t differ much from the ones taken by George W. Bush.

In Houston on Friday, he described himself as “open” to limitations on abortion. Like all Republican presidents since Reagan, he is denying he has a litmus test on abortion – but Rudy then takes the anti-litmus-test position to its logical conclusion.

Which is to say, he not only won’t ask what a judicial candidate’s views on abortion are, he wouldn’t even be surprised to see a judge he’d appointed support the overturning of Roe v. Wade on constitutional grounds or support its continuance on the grounds that it is a long-established precedent.

He even has gone so far as to say he is convinced by the logic of the recent appeals-court decision supporting the Second Amendment right to own guns in the District of Columbia – even though as mayor he actually sought to use his authority to impede the sales of guns in other jurisdictions.

In other words, he’s a pro-choice gun controller . . . except that he supports restrictions, is convinced that there is a Second Amendment right and wants to appoint the kinds of judges conservatives like.

I’m not sure what to make of this, frankly. It may have something to do with the confusing revolution that’s taking place in the way Republicans and Democrats will choose their nominees – a revolution that may push candidates to want to appeal to the center far earlier than they have in previous cycles.

In previous years, the primary calendar had Republicans instantly heading into the South after Iowa and New Hampshire began the electoral season. This had the effect of pushing the candidates to demonstrate their hard conservative credentials very early. Deviation from conservative orthodoxy was dangerous.

Now, however, the South has been superceded to some degree by what people are calling Super-Duper Tuesday. On Feb. 5, hugely populous states – California, New York, New Jersey, Illinois and Florida among them – will hold their primaries.

There’s some talk among political pros that this change in the calendar means the results in Iowa and New Hampshire are going to be even more important than they have been.

With all due respect, I think that view is insane. Candidates who want to score delegates from the big states won’t have months to spend doing door-to-door politicking in those tiny and meaningless states. They’ll need to raise colossal amounts of money to buy TV time in the top markets in the country – time that has to be paid for in advance.

And voters in these states are less interested in social issues than voters in the solid South. They will be far more focused on Iraq, international security, terrorism and taxes. And there are a lot of those fabled suburban Republicans to court – voters who tend to be far more moderate on matters like abortion.

If I’m following

the change-that’s-not-a-change correctly, Rudy is the only Republican candidate who appears to be taking the new primary calendar seriously and factoring it into his calculations.

He’s running as a conservative – or an 80 percent conservative, as he describes himself – while claiming to be a moderate.